Pressure fluid motor



. March 2, 1943. as. GARTIN 2,312,367

PRESSURE FLUID MOTOR Filed March 28, 1941 2 Sheets-Sheet i 219 26 Fig 25 2 //9 22 33 43 3Z Ziweniar: 4b jg EZWwrGIGarZi/h 4'9 3 3 a March 2, 1943. GARTIN 2,312,367

PRESSURE FLUID MOTOR Filed March 28, 1941 2 Sheets-Sheet 2 84 d4 fizven%n Patented Mar. 2, 1943 UNITED PRESSURE FLUID MOTOR Elmer G. Gartin, Claremont, N. H., assignor to Sullivan Machinery Company, a corporation of Massachusetts Application March28, 1941, Serial-No. 385,709

15 Claims.

This invention relates to pressure fluid motors, and more particularly to improvements in pressure fluid motors of the reciprocating 'piston type.

It is sometimes desirable, in certain types of work, such as drilling through materials that are comparatively soft, to deliver to the shank of a working tool comparatively light blows, and to deliver a large number of the blows in a given unit of time. To obtain a high efliciency for a fluid actuated motor of the hammer piston type, it is necessary to make some use of the expansive action of the pressure fluid delivered to the motor cylinder. By providing in a motor of such type, a fluid distribution means which first supplies pressure fluid to the motor cylinder for driving the piston in one direction, then cuts ofi the supply of pressure fluid while the fluid within the cylinder expands, and then supplies to the opposite end of the cylinder a pressure fluid for driving the piston in the opposite direction, there may be obtained a high efficiency of operation. Such fluid distribution may be obtained by providing a pair of valves that are movable relative to each other, and providing means controlled by the hammer piston for effecting a pressure fluid actuation of the valves. If the pressure fluid that forces the valves to. their closed positions can ,be vented from the valve mechanism while pressure fluid is acting in an expansive manner within the motor cylinder. for driving the hammer piston, and if this can be done without reducing appreciably the amount of the expansively acting pressure fluid, then a smaller pressure will be required for forcing the valve from its seat that controls the supply of pressure fluid to the c'pposite end of the cylinder, and the piston will be reversed soon after the expansive fluid. has released its working force.

It is an object of this invention to provide an improved fluid actuated motor. It is another object to provide an improved fluid distribution means for a fluid actuated motor of the hammer piston type. Still another object is. to provide in an improved fluid actuated motor an improved fluid distribution means that is operative to cf.- fect an increased rate of reciprocation of the hammer piston iordelivering a. large number of blows. to a working implement in a given unit of time. Still another object is to provide improved fluid distribution means tor ahammer motor and having a plurality of valves actuated by ressure fluid under the control of the hammer piston, the control being such that pressure fluid is vented from the valves during reciprocation of the piston without reducin appreciably the pressure fluid invention may assume in practice.

In these drawings:

Fig. 1 is a central longitudinal sectional view through a pressureflu-id motor constructedin accordance with an illustrative embodiment of the invention.

Figs. 2 and 3 are views similar to Fig. 1, showing the parts in difierent positions relative to each other.

Fig. 4 is a rear'elevational view of the rear valve.

Fig. 5 is a side elevational view of the valve shown in Fig. 4.

Fig. 6 is a front elevational view of the front valve.

Fig. 7 is aside elevational viewof the valve shown in .Fig. 6.

Fig. 8 is an enlarged fragmentary sectional View taken on the plane of Fig. 1, showing details of the improved fluid distributing means.

Fig. 9 is a longitudinal vertical sectional View showing apressure fluid motor constructed in accordance with another illustrative embodiment of the invention.

Figs. 10 and 11 are views similar to Fig. 9 showing the parts in different relative-positions.

Fig. 12 is a rear elevational view of the rear valve.

Fig. 13 is a side elevational view of the rear valve.

Fig. 14 is a front elevational view of the front valve.

Fig. 15 is a side elevational view of the front valve. I

Fig. 16 is an enlarged fragmentary sectional view taken on the plane of Fig. 9, showing details of the fluid distributing means.

In both illustrative embodiments of the invent-ion the improved pressure fluid motor is of the reciprocating piston, impact type adapted especially for delivering blows for the actuation of a drilling tool.

In the embodiment of the invention shown in Figs. 1 to 8, inclusive, the improved pressure fluid motprincludes a cylinder I having a'bore -2 in which a piston 3 is reciprocably contained. The motor pistonis, in this instance, in the form of a hammer and is adapted to deliver impact blows through a tappet A to the shank!) of a-workingim-plement. 'Ihe -tappet is reciprocably mounted in a bore in a front cylinder head i, and the shank of the working implement pro- Y jects within the bore in a position to receive the impact blows transmitted thereto by the tappet. A rear head block 9 is provided with a bore II] for receiving the rear end of the cylinder, and arranged within the bore I9 between the cylinder and the head block is a rear head plate I2 abutting the end of the cylinder and a valve block I3 abutting the head block. The front cylinder head and the rear head block are suitably secured to the motor cylinder, clamping the valve block I3 and the rear head plate I2 between the head block and the cylinder.

Formed in the valve block are coaxial bores I5, I6 and H, the bore I5 opening through the forward face of the block, the bore I6 being somewhat smaller and opening into the bore I5, and the bore ll being still smaller and opening into the bore I6 and through the rear face of the block. Concentric sleeve portions I8 and I9 are formed on the rear head plate I2 and project rearwardly into the bore I5, the sleeve portion I8 having a tight fit with the bore I5 and being somewhat longer than the inner sleeve portion I9. The bores I5, I6 and I1 and the sleeve portions I8 and I9 cooperate to form a valve chamber 29 in which a pair of cooperating, relatively movable, alined fluid distributing valves 2I and 22 are reoiprocably mounted. The distributing valves are preferably of the tubular sleeve type, the valve 2I having a sleeve portion 24 slidingly fitting'within the sleeve portion I3,

an external annular flange portion 25 slidingly its forward end slidingly fitting over the sleeve 7 portion 26 and has a portion 2'! between its ends slidingly fitting within the bore I6. its forward end it has an annular flange 28 fitting the bore I5, and at the forward end of the valve 22 is an annular portion 29 for en gaging an abutment 39 on the valve 2I in certain valve positions. mote faces of the valves 2| and 22 are annular portions 32 and 33 respectively, having surfaces that are adapted to seat against surfaces formed on the rear head plate I2 and the valve block I3 respectively, for controlling the flow of pressure fluid past the ends of the valves. The valves 2I and 22 have axial sleeve portions 35 and 36 extending from their remote ends and disposed radially inwardly of the annular portions 32 and 33 respectively, and these sleeve portions extend axially within the sleeve portion I9 on the rear head plate and the bore I! in the valve block I3 respectively, so that the inner wall of sleeve portion I9 and the wall of the bore I'l cooperate with the exterior peripheries of the sleeve portion 35 and 36 respectively, to provide restricted clearance spaces 31 and 38 for metering purposes, and thus control the quantity of fluid passing to the opposite ends of the cylinder 2 The sleeve 1 through passages later described. portions 35 and 36 surround openings 39 and 39' respectively, each communicating with an internal chamber 49 which the valves 2i and 22 cooperate to provide and to which pressure fluid may be supplied from any suitable source through a passage 4| opening into a chamber 42 formed in the rear head block and communicating with the bore IT in the valve block I3 and with the opening 39.

Near I Projecting from the rep When the front valve 2I is moved rearwardly from its seat, pressure fluid flows from the chamber 49 past the forward end of the valve to a. space 43 between the sleeve portions I8 and I9, and passages 44 extending through the rear head plate conduct pressure fluid from the space 43 to the rear end of the cylinder bore 2. Formed in the valve block at the rear end of the bore I6 is an annular groove 46, and a radially extending passage 41 in the valve block connects this groove to a passage 48 extending generally longitudinally through the rear head block and opening into a fluid distribution passage 49 formed in the cylinder I. The passage 49 communicates with the cylinder bore near its forward end through a port 50. When the valve 22 is moved forwardly from its seat, pressure fluid flows from the chamber 42 and, to some extent, from the chamber 40 past the rear face of the valve to the groove 46, and is conducted through the passages 47, 48 and 49 and port 59 to the forward end of the cylinder bore where it acts on the front end of the piston 3 and forces the latter rearwardly in the cylinder bore.

Formed in the valve block surrounding the bore I5 is an annular groove 52 opening into the valve chamber 20 between the annular valve flanges 25 and 28. A passage 54 in the valve block opens into the groove 52 and communicates with a passage 55 extending through the rear head plate. A passage 56 in the motor cylinder communicates with the passage 55 and is connected by a port 57 to the cylinder bore at a point uncovered by the piston after it has moved a relatively short distance in its forward stroke. When the forwardly moving piston uncovers the port 51, ressure fluid flows through the port and passages 56, 55 and 54 to the groove 52, where it is conducted to the space between the valve flanges 25 and 28 and acts to close the valve 2|, which is open at the start of the forward piston stroke,

and then to hold both valves firmly on their seats. Another passage 58 in the valve block opens into the groove 52 at a point shown as substantially opposite the passage 54 and communicates with a passage 59 extending through the rear head plate. A passage 66 in the motor cylinder communicates with the passage 59 and is connected to'the cylinder bore through a port 6| that is uncovered by the motor piston during its rearward stroke well before release. The bore I5 at the remote sides of the flanges 25 and 28 is connected through passages 63 and 64 to an annular groove 65 formed in the outer periphery of the valve block I 3, and the groove 65 is connected to atmosphere through passages 66 and 61. A vent passage 68 connects the passage 58 with the groove 65 so that pressure fluid conducted from the front end of the cylinder bore through port GI and passages 65, 59 and '58 will be partially vented and prevent an immediate building up of pressure between the valve flanges and a premature closing of the valve controlling the supply of pressure fluid to the forward end of the cylinder bore when the motor is being started. Communicating with the cylinder bore midway between the ends thereof is a piston controlled exhaust groove 69 connected to atmosphere through a passage I0 and a slot II. Formed in the periphery of the piston 3 is an annular groove I3, and the length of this groove and the location of the port 6| with respect to the exhaust groove 69 are such that in certain positions of the piston the port 6| is connected to atmosphere through the grooves I3 and 69. The port 51 is so located that it is never connected to the exhaust groove 69 through the groove 73. I

The mode of operation of the pressure fluid motor above described is :as follows. Assuming that pressure fluid is being supplied through the passage 4| to thechambers 42 and 40, and that the parts are in the positions shown in Fig. 1, pressure fluid will flow .past the front face of the valve 2i and be conducted through the passages 44 to the rear end of the cylinder bore, where it will act on the rear end of the piston 3 and start it in a forward direction. The forward end of the cylinder bore is vented .to atmosphere through the exhaust groove 69, the passage 16 and the slot 1 l, and the space between the valve flanges 25 and 28 is vented through passages 53, 59, 6B and port 6| into the forward end of the cylinder bore, and so to atmosphere, and also through passages 58, 68, groove 65 and passages 66 and El to atmosphere. The pressure of the fluid acting on the rear end of the piston also acts on the forward face of the valve 2|, holding it in its open position and in engagement with the valve 22 so that the latter valve is held firmly in its seated position. As the piston moves in a forward direction it first covers the exhaust groove 59, cutting off the venting of the forward end of the cylinder bore, except for the restricted venting through the passage 68, and then it uncovers the port 5! so that pressure fluid is supplied from the rear end of the cylinder bore through the port 51, the passages 56, 55, 54 and groove 52 to the space between the valve flanges 25 and 28, whereit acts to force the front valve to its seated position and to hold the rear valve on its seat. Though the space between the valve flanges is connected to the front end of the cylinder bore through the passages 58, 59 and 6!], When the port 51 is uncovered, it will be noted that the piston has at that time already covered the exhaust groove 69, and a compression pressure is commencing to be built up by the forward movement of the piston, and so, since the passage 88 is quite restricted, the moving of the front valve to its seat is assured. After the valve 2! is seated, the piston continues to be driven forward under the action of the expanding fluid in the rear end of the cylinder and its own momentum; and release will occur when the piston uncovers the exhaust groove 69. When the hammer piston reaches, in its forward travel, a position bringing its then-vented roove 13 opposite port BI and connecting the port 6| through the groove 13 momentarily to the exhaust groove 69, the pressure which has been acting to hold both valves seated is sufficiently reduced to permit opening of the valve 22 by compression pressure. The compressed fluid within the forward end of the cylinder bore flows through the port 50, passages 69, 48, A? and groove 46 to the valve chamber at the rear end of the valve 22, and, since the pressure between the valve flanges is reduced, the valve 22 is moved forwardly from its seat when the compression pressure is still comparatively low. That is, the valve 22 may be opened even before the piston uncovers the exhaust groove. By reason of the disposition of the throwing passages in spaced relation relative to the cylinder (instead of their being combined in one passage with two ports opening into the cylinder) the flow of fluid entering port 51 from the cylinder, to the front end of the latter, is so retarded that the desired delay of admission to the front end of the cylinder is definitely assured, and a higher pressure between the valve flanges is obtained until the piston groove connects port 6| with the exhaust l0. Were-ports and BI bq 'in p sage .69, say, theforward flowof fluidthrough 6|, when 51 was uncovered, might cause premature front .end admission. As soon :as the .valve moves from its seat, pressure fluid is supplied from the chamber 42 and to some extent the chamber 40, past the rear :face ,of the -;valve to the groove 46 and through passages 4: "418, and port 5!] to the forward end of the cylinder :bore, where it will act .on the piston to move the latter in a rearward direction after it has delivered a blow to the tappet 4. When the piston is in its extreme forward position, the exhaust groove '69 is uncovered by the rear end of the piston, venting all the pressure fluid from the rear end of the cylinder bore and from the space'between the valve flanges through the passages 54, 55, 55 and port 5?. It may be noted that early opening of valve 22 will be promoted by the interconnection of the cylinder ends while the piston is in the position of Fi 2, and for some interval thereafter.

As the piston moves rearwardly, it first covers the exhaust groove 69, cutting off the escape of fluid from the rear end of the cylinder bore, and then it uncovers the port 6I so that pressure fluid flows from the forward end of the cylinder bore through port BI, and passages-60,59 and-58 to the space between the valve flanges and moves the valve 22 to its seat. The supply of pressure fluid to the forward end of the cylinder bore is cut off, but the piston continues to be forced rearwardly by the expansion of pressure fluid within the cylinder bore until the exhaust groove 69 is uncovered by the rear end of the piston. The piston continues to move rearwardly due to its inertia and compresses fluid within the rear-end of the cylinder bore which acts on a portion of the forward face of the valve 2| and finally forces that valve from its seat so that pressure fluid is supplied again to the rear end of the cylinder bore. As the piston moves toward the rear end of the cylinder, it uncovers, as above noted, the exhaust groove 69 and pressure fluid is vented from the forward end of the cylinder bore and from the space between the valve flanges.

Due to the early reduction in pressure of the fluid acting in the space between the valve flanges on the forward stroke of the piston, and to the resultant early opening of the valve controlling the supply of pressure fluid to the forward end of the cylinder bore, the force of the blows delivered by the hammer piston to the tappet is somewhat reduced, but the reversing of the piston travel from a forward to a rearward direction takes place -more quickly and the number of blows struck by the piston is appreciably increased.

If the motor was started when the piston was at the front end of the cylinder, pressure fluid supplied to the forward end of the cylinder bore would move the piston rearwardly. When the port 6| was uncovered, pressure fluid would flow through passages 60, 59 and 58 to the space between the valve flanges and some fluid would be vented from the passage 58 through passage 58, groove 65 and passages 66 and 61. The amount of fluid vented would be enough to prevent the valve 22 from being closed immediately, and the piston would continue to be forced rearwardly until its inertia would be sufficient to cause its continued movement to compress fluid within the rear end of the cylinder bore for opening the valve 2 I.

The modification of the invention shown in Figs. 9 to 16 inclusive, is like that shown in the preferred form except for the construction of the valves and the elements forming the valve chamber. The parts of the modification that are identical to those of the preferred form will be given the same numbers.

In the modification the rear end of the cylinder 1 fits within the bore It in the rear head block 9, and arranged within the bore lfl between the end of the cylinder and the block 9 is a rear head plate 15 abutting the end of the cylinder, a valve block 16 next to the plate '15, and a rear cover plate 11 between the valve block and the head block. The plates 75 and 11 and the valve block 16 cooperate to form a valve chamber 18 within which relatively movable and interchangeable sleeve-type valves 79 and 80 are supported coaxially with the cylinder bore 2. The valve chamber is bounded externally by the Walls of bores 82 and 83 in the valve block and by the inner wall of a sleeve portion 84 formed on the plate 15 and fit closely within the bore 82 at the forward end of the latter. The valve 19 is provided with a projecting sleeve portion 85 slidingly fitting within the sleeve portion 84, an external annular flange 81 slidingly fitting the bore 82, an internal annular flange 88 and a rearwardly extending sleeve portion 89. The valve 88 has a sleeve portion 9E! slidingly fitting the bore 83, a sleeve portion 9! slidingly fitting over the sleeve portion 89 on the valve 80, an external annular flange 92 slidingly fitting the bore 82 and an internal annular flange 93. Formed on the cover plate l1 and extending axially into the valve chamber isa sleeve portion 95 that is closed at its forward end. Opening throughthe sleeve portion 95 are ports 9600mmunicating with the space surrounding the sleeve portion between the internal valve flanges 88 and 93. Clearances are provided between the inner peripheries of the internal valve flanges and the sleeve 95 to form restricted passages 9! and 9? for metering the flow of pressure fluid to the remote ends of the valve. Projecting from the outer faces of the valves 19 and Bil are annular portions 98 and 99 respectively, for engaging surfaces on the plates 15 and TI and controlling the flow of pressure fluid to the opposite ends of the cylinder bore. The open center of the sleeve 95 communicates at its rear end with a chamber I90 formed in part in the plate 11 and in part in the head block 9, and pressure fluid is supplied to this chamber through the passage 4!. Pressure fluid is supplied to the rear end of the cylinder bore through passages 44 under the control of valve 19, and is supplied to the front end of the cylinder bore through passage 49 under the control of valve 80. Valve throwing passages 56 and 6B communicate with the valve chamber between the valve flanges 81 and 92 and open into the cylinder bore at points between the exhaust groove 69 and the rear and front ends, respectively, of the cylinder bore. The valve chamber spaces at the outer sides of the valve flanges are vented to atmosphere through passages 66 and Bl. Formed in the periphery of the piston is the groove 13 for connecting the passage 69 to atmosphere on predetermined forward movement of the piston.

The operation of the modified form of the invention is similar to that of the preferred form. When the parts are in the positions shown in Fig. 9, pressure fluid flows from chamber ma through ports 96, through the restricted passage 91, past the front face of the valve 19 and through passages 44 to the rear end of the cylinder bore. The front end of the cylinder bore is vented through the exhaust groove 69. The

pressure fluid acting on the rear end of the piston moves it forwardly and, 'onpredetermined movement of the piston, pressure fluid is supplied through passage 55 to the valve chamber, where it acts on the valve flanges to close the front valve and hold the rear valve seated. After the piston moves a short distance further the passage 60 is connected through the groove 13 to the exhaust groove 69 for reducing the pressure of the fluid acting between-the flanges. Compression pressure built up Within the forward end of the cylinder bore during forwardmovement of the piston is conducted through passage 49 to the rear end of the valve chamber, where it acts to move the rear valve from its seat and connect the front end of the cylinder bore to pressure fluid supply from the chamber I00. The piston delivers a blow to the tappet and is then forced rearwardly by the supply of pressure fluid. As the piston moves rearwardly it first uncovers the passage 60 to supply pressure fluid to the valve chamber for moving the rear valve to its seat, then it uncovers the exhaust groove 69 for venting pressure fluid from the valve chamber, and then it establishes a compression pressure Within the rear end of the cylinder bore which forces the front valve from its seat for connecting the rear end of the cylinder to fluid supply. The relatively early opening of the valve controlling fluid supply to the front end of the cylinder takes place similarly to the operations described with respect to the first species.

As a result of this invention it will be noted that there is provided an improved pressure fluid motor having improved means for controlling the supply of pressure fluid to the motor cylinder. It will be further noted that by reason of the improved means-for controlling the supply of pressure fluid to themotor cylinder there is obtained an increase in the rate of reciprocation of the hammer piston. It will be evident that by the improved Valve design and the improved means for controlling the flow of pressure fluid relative to the valves, there is obtained an operation of the valves whereby pressure fluid is supplied to the motor cylinder to effect a high rate of reciprocation of the hammer piston for delivering a large number of blows to a tool in a given unit of time. Other advantages of the improved pressure fluid motor will be clearly apparent to those skilled in the art.

While there are in this application specifically described two forms which the invention may assume in practice, it will be understood that these forms of the same are shown for purposes of illustration and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent'is:

1. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, passage means connecting said valve chamber to the opposite ends of said cylinder bore, a pressure fluid supply communicating with said ing with said valve chamber at points spaced from eachother and controlled by said piston for subjecting pressure areas on said valves simultaneously to, valve throwing pressures, and means controlled by saidpiston for venting one of said throwingpassages-prior to release on certain strokes of said piston and eflecting an early throwing of .one .of said valves.

7 12. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, passage means connecting said valve chamber to the opposite ends of said cylinder bore, a pressure fluid supply communicating with said valve chamber, relatively movable valves in said valve chamber for controlling the flow of pressure fluid from said supply to said passage means respectively, means for throwing said valves into their diflerent operating positions including separate throwing passages communicating with said valve chamber at points spaced from each other and controlled by said piston for subjecting pressure areas on said valves simultaneously to .valve throwing pressures, an exhaust port controlled by said piston for venting pressure fluid from said cylinder bore, and a groove in said piston for connecting one of said throwing passages to said .exhaust port during certain strokes of said piston before said exhaust port is uncovered bysaid piston and thereby effecting an early throwing of one of said valves.

3. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and means forsupplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber, passage means connecting said valve chamber to the opposite ends of said cylinder bore, a pressure fluid supply communicating with said valve chamber, relatively movable valves in said valve chamber for controlling the flow of pressure fluid from said supply to said passage means respectively, means for throwing said valves into their difierent'operating positions including separate throwing passages communicating with said valve chamber at opposite sides of the latter and opening into said cylinder bore :at points spaced from its opposite ends, an exhaust port between the points of communication of said throwing passages with said cylinder bore and controlled by said piston for venting pressure fluid from said cylinder bore, and fluid conducting means formed in said piston for connecting one of said throwing passages to said exhaust port before the latter is uncovered on certain strokes of said piston.

4. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston ineluding means providing a valve chamber, passage means connecting said valve chamber to the opposite ends of said cylinder bore, a pressure fluid supply communicating with said valve chamber, relatively movable valves in said valve chamber for controlling the flow of pressure fluid from said supply to said passage means respectively, means for throwing said valves into'their different operating positions including separate throwing passages communicating with said valve chamber at opposite sides of the latter and opening into said cylinder bore at-points spaced from its opposite ends, an exhaust port between the points of communication of said'throwingpassages with said cylinder bore and controlled by said piston for venting pressure fluid from said cylinder bore, and fluid conducting means formed in said piston for connecting said throwing passage spaced from the front end of said cylinder bore in communication with said exhaust port before the latter is uncovered on the forward strokes of said piston.

5. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber hav ng coaxial valve receiving bores, a pressure fluid supply communicating with said valve chamber, passage means connecting the opposite ends of said valve chamber to the opposite ends of said cylinder bore, relatively movable sleeve-type valves reciprocable in said coaxial bores for controlling the flow of pressure fluid to said passage means respectively, oppositely directed pressure areas on said valve-s against which pressure fluid acts for forcing said valves toward their closed positions, means for controlling the flow of pressure fluid relative to said pressure areas including separate throwing passages communicating withsaid valve chamber at points spaced from each other, said separate throwing passages opening into said cylinder bore at points spaced from its opposite ends, a piston controlled exhaust-port for venting pressure fluid from said cylinder bore and-from said throwing passages through said cylinder bore, and fluid conducting means fOrmed in said piston for connecting the one of said throw-ing passages opening into the cylinder-bore nearest the end toward which said piston travels in cert ain of its strokes with said exhaust port before theother of said throwing passages is connected to exhaust.

6. In a pressure fluid motor, a cylinder having a bore, apiston reciprocable in said bore, and means for supplying pressure fluid to said cylinder;boreto effect reciprocation of said piston :in-

.cluding'means providing avalve chamber having coaxial valve receiving bores, a pressure fluid supply communicating with said valve chamber, passage means connecting the opposite ends of said valve chamber to the opposite ends of said cylinder bore, relatively movable sleeve type valves reciprocable in said coaxial bores for controlling the flow of pressure fluid to said passage means respectively, oppositely directed pressure areas on said valves against which pressure fluid acts for ,forcing said valves toward their closed positions, means for controlling the flow of pressure -fluid relative to said pressure areas including separate throwing passages communicating With said valve chamber at diametrically opposite points and. opening into said cylinder bore at points spaced from its opposite ends, a piston controlled exhaust port for venting pressure fluid fromsaid cylinder bore and from said throwing passages through said cylinder bore, and a fluid conducting groove formed in said piston for connecting the throwing passage opening into the cylinder bore at a point spaced from its forward end to said exhaust port during the forward strokes of said piston and before the other of said throwing passagesisconnected-to exhaust.

7. In apressure fluid motor, a cylinder having a bore, a piston reciprocableiin said bore, and means for supplying pressure fluid-to said cylinder bore to eflect reciprocation ofsaidpiston including means providinga valve chamber having coaxial valve receiving bores, apressure fluid supply communicating with said valve chamber, passage means connecting the opposite ends of said valve chamber to the opposite ends of said cylinder bore, relatively movable sleeve type valves reciprocable in said coaxial bores for controlling the flow of pressure fluid to said passage means respectively, pressure areas on said valves against which pressure fluid acts for forcing said valves toward their closed positions, means for controlling the flow of pressure fluid relative to said pressure areas including separate throwing passages communicating freely with said pressure areas at opposite sides of said valve chamber and opening into said cylinder bore at points spaced from its opposite ends, an exhaust port opening into said cylinder bore, and piston controlled means for connecting one of said throwing passages with said exhaust port at least once in each stroke of the piston.

8. In a pressure fluid motor, a cylinder having a bore, a, piston reciprocable in said bore, and means for supplying pressure fluid to said cylinder bore to effect reciprocation of said piston including means providing a valve chamber having coaxial valve receiving bores, a pressure fluid supply communicating with said valve chamber, passage means connecting the opposite ends of said valve chamber to the opposite ends of said cylinder bore, relatively movable sleeve type valves reciprocable in said coaxial bores for controlling the flow of pressure fluid to said passage means respectively, pressure areas on said valves against which pressure fluid acts for forcing said valves toward their closed positions, means for controlling the flow of pressure fluid relative to said pressure areas including throwing passages communicating freely with said pressureareas and opening into said cylinder bore at points spaced from its opposite ends, an exhaust port opening into said cylinder bore, piston controlled means for connecting said throwing passages with said exhaust port during reciprocation of said piston, and a restricted vent for'connecting one of said throwing passages continuously to atmosphere.

9. In a pressure fluid motor, a cylinder having a bore, a piston reciprocable in said bore, and means for supplying pressure fluid to the cylinder bore to effect reciprocation of said piston in-- cluding means providing a valve chamben passage means for conducting fluid from said valve chamber to the opposite ends of said cylinder bore respectively, a pressure fluid supply communicating with said valve chamber, valve means in said valve chamber for controlling the flow of pressure fluid from said valve chamber to said passage means respectively, means for throwing said valve means into different operating positions including throwing passages communicating with the valve chamber and opening into the cylinder bore at points spaced from the opposite ends of. the latter and also spaced from each other by a distance greater than the length of the piston, a piston controlled exhaust port between said points, and means forming a recess on said piston communicable with said'exhaust port in certain positions of said piston and with one of said throwing passages prior to the uncovering of said piston-controlled exhaust port by the end of the piston which is then approaching the point of communication of said throwing passage with said cylinder.

1Q. In a pressure fluid motor, the combination comprising a cylinder, a piston reciprocable in said cylinderjand fluid'distribution means for the motor including, means providing a, valve chamber comprising a large central bore and smaller end bores, fluid distribution passages leading from said chamber to the opposite ends of said cylinder respectively, a pressure fluid supply, a pair of cooperating fluid distributing valves of the sleeve type having sleeve portions arranged in sliding telescopic relation, outer sleeve portions connected to said first mentioned sleeve portions, said outer portions respectively slidingly fitting said smaller bores and carrying peripheral flanges fitting said larger bore, said valves being relatively movable and adapted to abut one another in certain positions thereof, and said valves controlling the flow of pressure fluid from said supply to said passages respectively, and means for throwing said valves into their different operating positions including separate throwing passages communicating with said larger bore at angularly spaced points between the inner sides of said valve flanges and controlled by said piston.

11. In a pressure fluid motor, the combination comprising a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for the motor including means providing a valve chamber, passages leading from said valve chamber respectively to the opposite ends of said cylinder, a pair of valves arranged in said valve chamber and movable relative to each other, an internal fluid supply chamber formed within said valves, said valves controlling the flow of pressure fluid from said supply chamber to said passages, and means for subjecting said valves to valve-throwing pressures for throwing said valves into different operating positions including surfaces on each of said valves cooperating in the formation of a space to which fluid is delivered to effect valve closure, means including separate passages controlled by said piston for delivering fluid to and venting fluid from said space, one of said passages uncovered and another covered on one pass of the piston, and the latter uncovered and the first covered during the opposite pass of the piston, and means for venting one of said passages through the cylinder end of the latter and through the cylinder while the piston is opposite the cylinder end of the same.

12". In a pressure fluid motor, the combination comprising a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for the motor including a plurality of stepped bores forming a valve chamber, passages leading from said valve chamber respectively to the opposite ends of said cylinder, a pair of valves of the sleeve type arranged in said valve chamber and movable relative to each other, an internal fluid supply chamber formed by said valves, said valves respectively controlling the flow of pressure fluid from said supp-1y chamber to said passages, said valves having sleeve portions projecting from their remote ends and cooperating with the walls of bores at the ends of said valve chamber for regulating the flow of pressure fluid to said passages, and means for subjecting said valves to valve-throwing pressures for throwing said valves into their different operating positions,

13. In a pressure fluid motor, in combination, a cylinder having a bore, a piston reciprocable in said cylinder bore, and fluid distribution means for supplying pressure fluid to and ex hausting fluid from said cylinder bore for effecting reciprocation of said piston comprising a plurality of stepped bores forming a valve chamber, passage means providing fluid supply passages for connecting the opposite ends oi" said valve chamber with the opposite ends of said cylinder bore, and a pair of cooperating, relatively movable, fluid distributing valves of the sleeve type arranged in said valve chamber and being interchangeable end for end Without affecting their operating functions, said valves arranged in sliding telescopic relation and mounted in said valve chamber for respectively controlling fluid flow to said supply passages, means for supplying pressure fluid to said valve chamber for forcing said valves to their seats including passage opening into said valve chamber between said valves and controlled by said piston and having their piston-controlled ends spaced a distance greater than the length of said piston, and means on said piston for connecting one of said last mentioned passages to atmosphere at least once during each piston stroke.

14. In a pressure fluid motor, in combination, a cylinder having a bore, a piston reciprocable in said cylinder bore, and fluid distribution means for supplying pressure fluid to and. exhausting fluid from said cylinder bore for effecting reciprocation of said piston comprising means providing a valve chamber, and a pair of cooperating, relatively movable, fluid distributing valves having like operating functions and being interchangeable end for end without affecting their operating functions, said valves always engaging one another and cooperating to provide a space therebetween, means forming passages leading from said valve chamber to the opposite ends of said cylinder bore at the opposite ends of said piston respectively, said passages controlled by said valves respectively for conducting pressure fluid from said valve chamber to said cylinder bore, and throwing passage means communicating with the cylinder bore and controlled by said piston for conducting throwing pressure to the space between said valves, said piston having thereon means operative to eflect discharge of fluid from one of said throwing passage means during portions of the reciprocations of said piston.

15. In a pressure fluid motor, in combination, a cylinder, a piston reciprocable in said cylinder, and fluid distribution means for the motor including a plurality of stepped bores forming a valve chamber, a pair of relatively movable sleeve-type valves arranged in said valve chamber and having sleeve portions in continuous telescopic relation with each other, said valves having external flange portions slidably fitting a central bore bounding said valve chamber, piston controlled means for supplying pressure fluid to said external flanges and effecting closure of said valves, sleeve portions on said valves fitting respectively the bores bounding the ends of said valve chamber, internal flange portions formed on said valves, a stationary sleeve portion extending axially into said valve chamber, means for supplying pressure fluid through said stationary sleeve portion to the space between said internal valve flanges, fluid supply passages leading from said valve chamber to the opposite ends of said cylinder bore, said valves controlling the flow of pressure fluid from the space between the internal valve flanges to said supply passages, and said internal valve flanges cooperating with said stationary sleeve to provide passage means regulating the flow of pressure fluid to said supply passages.

ELMER G. GARTIN. 

